Devices capable of producing light of different wavelengths (e.g., devices comprised of solid-state light emitters such as light emitting diodes (LEDs), or devices comprised of gas discharge lamps) have allowed the construction of illumination and display devices capable of producing light of varied spectral content. The intensity of such a device may be controlled by changing the intensities of the device's individual emitters, and the spectral content of light produced by such a device may be controlled by changing the ratios of intensities of the device's different wavelength emitters.
Exemplary apparatus for controlling the spectral content of light produced by a solid-state illumination device is disclosed in U.S. Pat. Nos. 6,344,641, 6,448,550 and 6,507,159.